Field
The present disclosure relates generally to communication systems, and more particularly, to the conveyance of a modulation and coding scheme (MCS) of a control channel.
Background
Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). LTE is designed to support mobile broadband access through improved spectral efficiency, lowered costs, and improved services using OFDMA on the downlink, SC-FDMA on the uplink, and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.
User equipments (UEs) may need to transmit channel quality information (CQI) to base station so that base station can perform downlink scheduling. UEs with different signal-to-noise ratio (SNR) levels may have the capacity to transmit different number of CQI bits. For example, UEs that are located close to base station may transmit a higher number of CQI bits and UEs that are located at cell edge may transmit a lower number of CQI bits. If a fixed number of bits are used to transmit CQI, UEs with poor SNR may not be able to transmit CQI to the base station reliably.